TDK Propulsion » formulation

New Blue, pt. 2

David Reese — Tue, 16 Mar 2010 20:35:52 +0000

This weekend, I ran a 480 load of the new blue at a lower pressure (400 psi instead of ~600 like last time). The result:

Aerotech I357

TDK I300

OH YEAH. The one drawback was that this motor was not nearly as loud and generally “nasty” sounding as the higher pressure one. This was down at a Kn of 180, and operation was completely smooth, coming up to pressure and shutting down cleanly. I like this a lot. I have a 54/1050 and two 38/640s of this stuff ready to go next…

Solving Burn Rates

David Reese — Wed, 17 Jun 2009 17:38:41 +0000

For the new blue, I’ve been trying to characterize rate data from motor burns, rather than from strand burn data or burn rate motor testing. (It’s more fun to static test a motor than it is to do a strand burn test.) More on the maths later, but here’s the results so far:

New Blue

David Reese — Mon, 08 Jun 2009 08:38:52 +0000

I’ve been working on a new blue formula as of late. Consider this the first “official release”. It was conceived in January, first fired in April, and first fired with data last weekend. It’s a smokeless variant of the typical blue I’ve flown in the past — 1% CuO, 2% Al — with the goal of getting something “Blue Thunder“-like. The story of the first flight is up in a blog post on OurPlanet.

First reactions from the flight were: (1) Not quite as fast as Blue Thunder, but certainly nice nonetheless, and (2) Oh my, look at that flame separation. Data from static testing showed that this burn was only at ~570 PSI, but the flame stands off nicely, even at low chamber pressures. It turns out to be about as fast as Kosdon fast, at least per the data. Here’s a typical curve from a Loki 38/480 firing:

Delivered Isp is somewhere around 200 sec, so nothing too special — just another “knob” propellant to add to the fray. Formula and rate data after the jump.

“SA Blue” (named such as I envisioned doing this in a C-slot for a Standard Arm I’m building) is 2% Al 400, 1% CuO, 80% solids with all 200 mic AP. Pretty much as simple as you can make it. But I like how it performs; not much to no slag on the nozzle, and a lot tamer than high CuO formulations (Amarillo Blue, I’m lookin at you…). Initial data says r = 0.0175P_c^0.42 (P_c in PSI) with a theoretical C* of 4632 ft/sec, safe to run between Kn = 200 and 300 in most situations. Maybe one day I’ll try it in a 2550 — right now it looks like just over 900 PSI and a 1.8 sec burn. L1500 anyone? Maybe after it’s better characterized…